My program seems to run into an infinite loop when display function is called

Question

The following excerpt works to create a new object of class 'contact'. The create_contact function works to get new data through member function getdata() and hence create a new contact and attach it to a file 'contact_diary' in a sorted manner. The display function reads that file to display the list on screen through class member function 'pudata()'. However, some junk data is getting accounted for in these create and display functions. Please suggest corrections.

void create_contact(){
    contact p,q;    //objects
    cout<<"Enter data for new contact...";
    p.getdata();
    contact_diary_renew(); //this function opens and closes a file in out mode 
                           //to refresh it's contnts

    fin.open("contact_diary.txt",ios::binary|ios::in);
    fin.seekg(0);

    if(fin.eof()){             //when file is empty
        fout.open("contact_diary.txt",ios::binary|ios::out);
        fout.seekp(0);
        fout.write((char*)&p,sizeof(p));
        fout.close();
    }

    else{                       //when file is not empty
        int position=0,i;
        fin.seekg(0);

        while(!fin.eof()){  //to get location to enter new data

            fin.read((char*)&q,sizeof(q));

            if(strcmp(p.givename(),q.givename())<=0){
                break;
            }

            else{
                position+=1;
                fin.read((char*)&q,sizeof(q));
            }

        }

        fout.open("temp.txt",ios::binary|ios::out); //temporary file 

        fin.seekg(0);
        fout.seekp(0);

        for(i=0;i<position;i++){
            fin.read((char*)&q,sizeof(q));
            fout.write((char*)&q,sizeof(q));
        }

        fout.write((char*)&p,sizeof(p));

        while(!fin.eof()){
            fin.read((char*)&q,sizeof(q));
            fout.write((char*)&q,sizeof(q));
        }

        remove("contact_diary.txt");
        rename("temp.txt","contact_diary.txt");

        fout.close();
    }

    fin.close();
    cout<<"New contact created successfully!"<<endl;
    getch();
}

void display_contacts(){     //function to display the list
    contact p;  //object
    int count=0;

    fin.open("contact_diary.txt",ios::binary|ios::in);
    fin.seekg(0);

    while(!fin.eof()){
        fin.read((char*)&p,sizeof(p));
        p.showdata();
        count+=1;
    }

    if(count==0){
        cout<<"List empty!"<<endl;
    }

    else{
        cout<<"Total number of contacts: "<<count<<endl;
    }

    fin.close();
    getch();
}